AA 203 doubler failure? (1 Viewer)

[Mark W]

Has anyone here experienced the AA replacement output shaft in their 203 doubler snapping?

A couple of years ago a friend/customer had a newly installed one snap (the load in the drivetrain did not affect the stock 3 speed case at all).

Yesterday the shaft in my rig failed... the rig is sitting beside the trail 100 miles from the road waiting to get the replacement part and a rescue/repair trip.

Not happy about this and rethinking my drivetrain setup. Failures this far from the road are not a casual thing to deal with. Wondering if others have encountered this failure in their AA conversion kits?


Mark...

 

[Isotel]

Call Jerry Nichols! he knows them in and out! Im sure he dose not know about every failure, but should be able to give some incite.. PM if you need the #

and good luck on the recovery, its fun to leave a rig behind!

 

[scouthead]

What happened when it failed? I had thought of doing this with my project '73, and have backed off to rethink things after hearing a few people's takes on the subject...

current production of a lot of AA shafts involves some pressure welding (as do other brands)... and this can cause weak points?...
anyone know how the above mentioned (and failed) shaft is manufactured? From billet? Anything pressure welded? Cut splines? Rolled splines?

Also the split case I wanted to use is from a late model fj60, and has 19 splines...
while trying to find out if the doubler can be had for this case, I have been told by two people that there AREN'T any 19 spline cases...

It's sitting in my garage right now, AND I CAN COUNT TO 20!

 

[Josie'sLandCruiser]

Hi All:

Mark, sorry to hear about this problem! That is gonna be quite the recovery job!

So, this AA replacement shaft, it connects the 203 GRB to the TLC t-case, correct?

Regards,

Alan
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Has anyone here experienced the AA replacement output shaft in their 203 doubler snapping?

A couple of years ago a friend/customer had a newly installed one snap (the load in the drivetrain did not affect the stock 3 speed case at all).

Yesterday the shaft in my rig failed... the rig is sitting beside the trail 100 miles from the road waiting to get the replacement part and a rescue/repair trip.

Not happy about this and rethinking my drivetrain setup. Failures this far from the road are not a casual thing to deal with. Wondering if others have encountered this failure in their AA conversion kits?


Mark...

 

[Josie'sLandCruiser]

Hi All:

Well, a buddy of mine (Mike) did a (FJ60) H42/203GRB/split t-case swap a few years ago so it was available at some point.

Don't think this is correct. Mike used an early (1982 or 83) H42 and 'split case for his 203GRB swap, to obtain the 2.28 low range that the early FJ60 came with.

Regards,

Alan

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<snip>

Also the split case I wanted to use is from a late model fj60, and has 19 splines...
while trying to find out if the doubler can be had for this case, I have been told by two people that there AREN'T any 19 spline cases...

It's sitting in my garage right now, AND I CAN COUNT TO 20!

 

[boots4]

AA doesn't show a 19 spline adapter for the toyota tcase on their site, BUT if you call Jerry Nicoles he can get an adapter for you. I picked one up 1.5 yrs ago for a 203 to a 1985 FJ60 splitcase so they are available but you have to go through Jerry to get one. The 203 doubler is quite stout, the gears are sizable larger than my splitcase stuff so that's crazy that it broke and not the tcase behind it.

I'm assuming that you are running a 16 spline adapter into the 3 speed case right Mark W?

The adapting shaft on the left. MARK W, This is the shaft that broke, correct (just in the 16 spline flavor)? Original 203 shaft on the right.

Ready to bolt to the splitcase.

 

[sixty]

Mark,

I have no experience with the cruiser kits, but I would think the 3spd case outputs (10spl?) and the split case outputs would be totally different. Which one failed?

I'd go 203 to 205 & build a centered rear axle.

 

[Mark W]

The kit is available for the 19 spine... only through Jerry. AA , makes it just like the kit for the earlier units, but it is a propriatory deal with Jerry. Only he sells it.

To be honest, that is not what I care about here. I have snapped the shaft (yes, the one pictured) in my 16 spline conversion kit in front of my Orion Tcase. The other one that we snapped was either a 10 spline or 16 spline in front of a stock tcase ( I do not remember right this second and have not checked yet).

I am going to have to replace it to get the rig off the trail. But I am pondering if I want to do away with this setup if in fact this shaft failure is a problem that others have had too. I Looking for any first or even second hand knowledge of AA 203 doulber failures.

The first one we broke was under load (clawing through a deep mudhole), but not enough to hurt the stock Tcase that was behind the 203. This time there was no significant load on the drivetrain when it let go, and in general the drivetrain of this rig is not stressed to extreme levels.


Mark...

 

[boots4]

To be honest, that is not what I care about here.

True, I was mostly answering another's question. It will be interesting to see where it broke. Honestly you're the first one I've heard about it snapping but I'm not on the 40s forum much. Just a couple of questions to see if it supports any of my personal theories. These apply to any failures you or others have heard of or had if you don't mind sharing.

Was the 203 in Low at time of breakage?
Do you or your friend with the failure typically engage the 203 in low first and then the low in the tcase?
Did you replace bearings/bushings when you originally put it together?

 

[Gumby]

I have had no issues with mine. I have broken three cruiser transfer cases for various reasons, but no issues with the 203 or the adapter at all.

I'm only running a stock 2:1 cruiser case though. Not a 4:1 Orion. I also run an auto with less gearing and less shock load than a 420 or 465.

 

[Mark W]

I talked to AA today and after some discussion in house, they responded that while it is rare, they have seen a few shaft failures. The feeling was that it is more common with the 16 spine shafts and it is usually right at the step down point on the shaft (where our other rig broke and where it seems that this one has. It is usually in very hard use rigs.
I personally do not feel that my rig is used in such a way that it should have taxed this component. I have large tires (39.5X18 boggers), but I also have 5.29 gears and when I do need power it is in deep mud or steep hills... very little high traction high horse power situations. Lots and lots of running over slow speed rough trail at low power.

Answering the questions above... both of the 203s were in low when they failed, ALL bearings and bushing in each were brand new when the conversion was done. The selection of low or high range in the two boxes varies depending on the trail. 8:1 is seldom used, but 2:1 or 4:1 changes all the time as trail conditions warrant.


Mark...

 

[warpdriv]

I've been running a 700R4/NP203/TLC 3sp case (my stock 1970 case) for 6 years with no problem. I have broken a lot of axle parts.

Hope this help. Best of luck.

 

[Mace]

Mark do you know if the output shaft was a resplined stock 203 unit or a custom new unit?

I can see the shaft splitting there if it was not hardened properly.

I have a 203/splitcase in my 60. So far so good..

Denny Mann used to have that same setup in his cruiser buggy. He broke rear axle shafts left and right and, to the best of my knowledge, never did manage to kill the 203/split tcase.

 

[Fromage]

Mark,

I would be interested in finding out how the shaft was made. If it is a machined down OEM shaft, getting the hardness just right might be problematic, which would account for some lasting and some of them breaking. maybe when you pull it out hit it with a file and see how deep the hardness runs?

I have seen accounts of many failures of re-cut shafts used between NP203s and 205s by the fullsize guys. You can now get brand new adapter shafts for that application in high-grade steel and it seems to have solved the issue. I think Northwest Fab sells the 203-205 adapters. Maybe this part needs to be made the same way, from scratch, out of high-grade stuff.

Good luck, that is a nasty part to have break in the woods.

 

[Mark W]

Update on this for anyone whi may be interested. The shaft did in fact break right where I expected... same spot as others have experienced. Unlike what I expected, there were no signs of pre-existing cracks... not that I could detect after the crunching of the complete failure anyway.

No damage to the input gear or any other component. Once we reached the rig, the repair went smoothly.
I have a ten spline shaft already and I am going to get a 10 spline input gear for the Orion... this shaft is larger in overall diameter and also at the root of the splines.
Although I am considering swapping out the 465/203 for an H41/Toybox to run ahead of the Orion.


This is the remains of the shaft sticking out og the back of the 203...

This is the shaft still in the input gear of the orion.

Both sides of the break

Busted shaft and replacement

Mark...

 

[Cruiserdrew]

Great pictures and an interesting problem.

Has this been mostly a feature with the 16 spline shafts?

Curious if there has been a problem with the 19 spline shafts for split case?

 

[Mark W]

When I contacted AA the first comments were that they had never seen this... I told them that it was the second one I had personal experience with... a few minutes on hold while he talked to some of the others there and the answer was that they have seen "rare" failures... always the 16 spline shaft IIRC. And always at this spot.

Mark...

 

[tlcbj73]

Hi,

Very interesting subject thank you Mark W

. I use your post to know if a person few to say to me if AA are in vacancy, because I will like to order a kit to adapt my np203 to my hj60 t-case (19 spline) and I still didn't have answer?! Who else could sell me this kit on the web by knowing that I live in France? (Mudrak for example? MCC - Mudrak Custom Cruiser - FJ60 Doubler ) Please help me because I absolutely need this kit to progress in my project

Thanks

 

[Mark W]

The kit to adapt the 19 spline Cruiser transmission and transfercase to work with the NP203 is made by AA as a propriety item for Jerry Nichols. You can buy it direct from Jerry or one of his distributors. Gary (Mudrak) is one of them.

AA is still in business and any rumors otherwise are baseless.


Mark...

 

[tlcbj73]

Ok thank you Mark.
I have just sent an e-mail to mudrak, I hope to have a positive answer